How do I get TWRP installed on my Verizon Samsung S3 (rooted)?

[Bennybrew]

I have sucessfully rooted my phone using towelroot and attempted to installed TWRP before doing any kind of flashing. However, each method I try seems to not work for one reason or another.

I have tried to use Odin, but I consistently get this string:
<ID:0/004> Added!!
<ID:0/004> Odin v.3 engine (ID:4)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> SingleDownload.
<ID:0/004> recovery.img
<ID:0/004> NAND Write Start!!
<ID:0/004> FAIL! (Auth)
<ID:0/004>
<ID:0/004> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

I have tried to download using an app called TWRP Manager. It does sucessfully download it, but when it comes to installing it consistently fails and asks for me to reboot the app and try again.

Any ideas? Sorry if this post comes off as dumb, I'm new to the whole thing and don't want to make a stupid mistake. I am running android 4.4.2 right now.

 

[Rukbat]

Have you read TeamWin Projects - TWRP 2.8 - Samsung Galaxy S3 (Verizon) | TeamWin ?

Are you installing Techerrata Downloads - Downloading openrecovery-twrp-2.8.3.0-d2vzw.tar ? (That's a direct download link - you can download the file from there [it'll start automatically in 10 seconds] and install it with Odin.)

Oops, wait - 4.4.2? The bootloader is locked. Try Safestrap. Look at [RECOVERY LOCKED/NE1] Unofficial Safestrap R… | Verizon Samsung Galaxy S III | XDA Forums

It works the same as TWRP, since it's a modified TWRP (but it's not the recovery, it intercepts the boot, since you can't install a new recovery with a locked bootloader), but gives you extra ROM slots, so you can keep a couple of ROMs in the phone at the same time and choose which one to run by restarting.)